Commit | Line | Data |
---|---|---|
98399780 | 1 | /* Return the canonical absolute name of a given file. |
c0c3707f | 2 | Copyright (C) 1996-2019 Free Software Foundation, Inc. |
98399780 YQ |
3 | This file is part of the GNU C Library. |
4 | ||
5 | This program is free software: you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 3 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
c0c3707f | 16 | along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
98399780 YQ |
17 | |
18 | #ifndef _LIBC | |
4a626d0a PA |
19 | /* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc |
20 | optimizes away the name == NULL test below. */ | |
21 | # define _GL_ARG_NONNULL(params) | |
22 | ||
98399780 YQ |
23 | # define _GL_USE_STDLIB_ALLOC 1 |
24 | # include <config.h> | |
25 | #endif | |
26 | ||
27 | #if !HAVE_CANONICALIZE_FILE_NAME || !FUNC_REALPATH_WORKS || defined _LIBC | |
28 | ||
98399780 YQ |
29 | /* Specification. */ |
30 | #include <stdlib.h> | |
31 | ||
32 | #include <alloca.h> | |
33 | #include <string.h> | |
34 | #include <unistd.h> | |
35 | #include <limits.h> | |
36 | #if HAVE_SYS_PARAM_H || defined _LIBC | |
37 | # include <sys/param.h> | |
38 | #endif | |
39 | #include <sys/stat.h> | |
40 | #include <errno.h> | |
41 | #include <stddef.h> | |
42 | ||
43 | #ifdef _LIBC | |
44 | # include <shlib-compat.h> | |
45 | #else | |
46 | # define SHLIB_COMPAT(lib, introduced, obsoleted) 0 | |
47 | # define versioned_symbol(lib, local, symbol, version) extern int dummy | |
48 | # define compat_symbol(lib, local, symbol, version) | |
49 | # define weak_alias(local, symbol) | |
50 | # define __canonicalize_file_name canonicalize_file_name | |
51 | # define __realpath realpath | |
52 | # include "pathmax.h" | |
53 | # include "malloca.h" | |
54 | # include "dosname.h" | |
55 | # if HAVE_GETCWD | |
56 | # if IN_RELOCWRAPPER | |
57 | /* When building the relocatable program wrapper, use the system's getcwd | |
58 | function, not the gnulib override, otherwise we would get a link error. | |
59 | */ | |
60 | # undef getcwd | |
61 | # endif | |
c0c3707f CB |
62 | # if defined VMS && !defined getcwd |
63 | /* We want the directory in Unix syntax, not in VMS syntax. | |
64 | The gnulib override of 'getcwd' takes 2 arguments; the original VMS | |
65 | 'getcwd' takes 3 arguments. */ | |
98399780 YQ |
66 | # define __getcwd(buf, max) getcwd (buf, max, 0) |
67 | # else | |
68 | # define __getcwd getcwd | |
69 | # endif | |
70 | # else | |
71 | # define __getcwd(buf, max) getwd (buf) | |
72 | # endif | |
73 | # define __readlink readlink | |
74 | # define __set_errno(e) errno = (e) | |
75 | # ifndef MAXSYMLINKS | |
76 | # ifdef SYMLOOP_MAX | |
77 | # define MAXSYMLINKS SYMLOOP_MAX | |
78 | # else | |
79 | # define MAXSYMLINKS 20 | |
80 | # endif | |
81 | # endif | |
82 | #endif | |
83 | ||
84 | #ifndef DOUBLE_SLASH_IS_DISTINCT_ROOT | |
85 | # define DOUBLE_SLASH_IS_DISTINCT_ROOT 0 | |
86 | #endif | |
87 | ||
4c62b19f PA |
88 | /* Define this independently so that stdint.h is not a prerequisite. */ |
89 | #ifndef SIZE_MAX | |
90 | # define SIZE_MAX ((size_t) -1) | |
91 | #endif | |
92 | ||
98399780 | 93 | #if !FUNC_REALPATH_WORKS || defined _LIBC |
49e4877c PA |
94 | |
95 | static void | |
96 | alloc_failed (void) | |
97 | { | |
c0c3707f | 98 | #if defined _WIN32 && ! defined __CYGWIN__ |
49e4877c | 99 | /* Avoid errno problem without using the malloc or realloc modules; see: |
c0c3707f | 100 | https://lists.gnu.org/r/bug-gnulib/2016-08/msg00025.html */ |
49e4877c PA |
101 | errno = ENOMEM; |
102 | #endif | |
103 | } | |
104 | ||
98399780 YQ |
105 | /* Return the canonical absolute name of file NAME. A canonical name |
106 | does not contain any ".", ".." components nor any repeated path | |
107 | separators ('/') or symlinks. All path components must exist. If | |
108 | RESOLVED is null, the result is malloc'd; otherwise, if the | |
109 | canonical name is PATH_MAX chars or more, returns null with 'errno' | |
110 | set to ENAMETOOLONG; if the name fits in fewer than PATH_MAX chars, | |
111 | returns the name in RESOLVED. If the name cannot be resolved and | |
112 | RESOLVED is non-NULL, it contains the path of the first component | |
113 | that cannot be resolved. If the path can be resolved, RESOLVED | |
114 | holds the same value as the value returned. */ | |
115 | ||
116 | char * | |
117 | __realpath (const char *name, char *resolved) | |
118 | { | |
119 | char *rpath, *dest, *extra_buf = NULL; | |
120 | const char *start, *end, *rpath_limit; | |
121 | long int path_max; | |
122 | int num_links = 0; | |
123 | size_t prefix_len; | |
124 | ||
125 | if (name == NULL) | |
126 | { | |
127 | /* As per Single Unix Specification V2 we must return an error if | |
128 | either parameter is a null pointer. We extend this to allow | |
129 | the RESOLVED parameter to be NULL in case the we are expected to | |
130 | allocate the room for the return value. */ | |
131 | __set_errno (EINVAL); | |
132 | return NULL; | |
133 | } | |
134 | ||
135 | if (name[0] == '\0') | |
136 | { | |
137 | /* As per Single Unix Specification V2 we must return an error if | |
138 | the name argument points to an empty string. */ | |
139 | __set_errno (ENOENT); | |
140 | return NULL; | |
141 | } | |
142 | ||
143 | #ifdef PATH_MAX | |
144 | path_max = PATH_MAX; | |
145 | #else | |
146 | path_max = pathconf (name, _PC_PATH_MAX); | |
147 | if (path_max <= 0) | |
148 | path_max = 8192; | |
149 | #endif | |
150 | ||
151 | if (resolved == NULL) | |
152 | { | |
153 | rpath = malloc (path_max); | |
154 | if (rpath == NULL) | |
155 | { | |
49e4877c | 156 | alloc_failed (); |
98399780 YQ |
157 | return NULL; |
158 | } | |
159 | } | |
160 | else | |
161 | rpath = resolved; | |
162 | rpath_limit = rpath + path_max; | |
163 | ||
164 | /* This is always zero for Posix hosts, but can be 2 for MS-Windows | |
165 | and MS-DOS X:/foo/bar file names. */ | |
166 | prefix_len = FILE_SYSTEM_PREFIX_LEN (name); | |
167 | ||
168 | if (!IS_ABSOLUTE_FILE_NAME (name)) | |
169 | { | |
170 | if (!__getcwd (rpath, path_max)) | |
171 | { | |
172 | rpath[0] = '\0'; | |
173 | goto error; | |
174 | } | |
175 | dest = strchr (rpath, '\0'); | |
176 | start = name; | |
177 | prefix_len = FILE_SYSTEM_PREFIX_LEN (rpath); | |
178 | } | |
179 | else | |
180 | { | |
181 | dest = rpath; | |
182 | if (prefix_len) | |
183 | { | |
184 | memcpy (rpath, name, prefix_len); | |
185 | dest += prefix_len; | |
186 | } | |
187 | *dest++ = '/'; | |
188 | if (DOUBLE_SLASH_IS_DISTINCT_ROOT) | |
189 | { | |
190 | if (ISSLASH (name[1]) && !ISSLASH (name[2]) && !prefix_len) | |
191 | *dest++ = '/'; | |
192 | *dest = '\0'; | |
193 | } | |
194 | start = name + prefix_len; | |
195 | } | |
196 | ||
197 | for (end = start; *start; start = end) | |
198 | { | |
199 | #ifdef _LIBC | |
200 | struct stat64 st; | |
201 | #else | |
202 | struct stat st; | |
203 | #endif | |
98399780 YQ |
204 | |
205 | /* Skip sequence of multiple path-separators. */ | |
206 | while (ISSLASH (*start)) | |
207 | ++start; | |
208 | ||
209 | /* Find end of path component. */ | |
210 | for (end = start; *end && !ISSLASH (*end); ++end) | |
211 | /* Nothing. */; | |
212 | ||
213 | if (end - start == 0) | |
214 | break; | |
215 | else if (end - start == 1 && start[0] == '.') | |
216 | /* nothing */; | |
217 | else if (end - start == 2 && start[0] == '.' && start[1] == '.') | |
218 | { | |
219 | /* Back up to previous component, ignore if at root already. */ | |
220 | if (dest > rpath + prefix_len + 1) | |
221 | for (--dest; dest > rpath && !ISSLASH (dest[-1]); --dest) | |
222 | continue; | |
223 | if (DOUBLE_SLASH_IS_DISTINCT_ROOT | |
224 | && dest == rpath + 1 && !prefix_len | |
225 | && ISSLASH (*dest) && !ISSLASH (dest[1])) | |
226 | dest++; | |
227 | } | |
228 | else | |
229 | { | |
230 | size_t new_size; | |
231 | ||
232 | if (!ISSLASH (dest[-1])) | |
233 | *dest++ = '/'; | |
234 | ||
235 | if (dest + (end - start) >= rpath_limit) | |
236 | { | |
237 | ptrdiff_t dest_offset = dest - rpath; | |
238 | char *new_rpath; | |
239 | ||
240 | if (resolved) | |
241 | { | |
242 | __set_errno (ENAMETOOLONG); | |
243 | if (dest > rpath + prefix_len + 1) | |
244 | dest--; | |
245 | *dest = '\0'; | |
246 | goto error; | |
247 | } | |
248 | new_size = rpath_limit - rpath; | |
249 | if (end - start + 1 > path_max) | |
250 | new_size += end - start + 1; | |
251 | else | |
252 | new_size += path_max; | |
253 | new_rpath = (char *) realloc (rpath, new_size); | |
254 | if (new_rpath == NULL) | |
255 | { | |
49e4877c | 256 | alloc_failed (); |
98399780 YQ |
257 | goto error; |
258 | } | |
259 | rpath = new_rpath; | |
260 | rpath_limit = rpath + new_size; | |
261 | ||
262 | dest = rpath + dest_offset; | |
263 | } | |
264 | ||
265 | #ifdef _LIBC | |
266 | dest = __mempcpy (dest, start, end - start); | |
267 | #else | |
268 | memcpy (dest, start, end - start); | |
269 | dest += end - start; | |
270 | #endif | |
271 | *dest = '\0'; | |
272 | ||
c0c3707f CB |
273 | /* FIXME: if lstat fails with errno == EOVERFLOW, |
274 | the entry exists. */ | |
98399780 YQ |
275 | #ifdef _LIBC |
276 | if (__lxstat64 (_STAT_VER, rpath, &st) < 0) | |
277 | #else | |
278 | if (lstat (rpath, &st) < 0) | |
279 | #endif | |
280 | goto error; | |
281 | ||
282 | if (S_ISLNK (st.st_mode)) | |
283 | { | |
284 | char *buf; | |
285 | size_t len; | |
4c62b19f | 286 | ssize_t n; |
98399780 YQ |
287 | |
288 | if (++num_links > MAXSYMLINKS) | |
289 | { | |
290 | __set_errno (ELOOP); | |
291 | goto error; | |
292 | } | |
293 | ||
294 | buf = malloca (path_max); | |
295 | if (!buf) | |
296 | { | |
49e4877c | 297 | __set_errno (ENOMEM); |
98399780 YQ |
298 | goto error; |
299 | } | |
300 | ||
301 | n = __readlink (rpath, buf, path_max - 1); | |
302 | if (n < 0) | |
303 | { | |
304 | int saved_errno = errno; | |
305 | freea (buf); | |
49e4877c | 306 | __set_errno (saved_errno); |
98399780 YQ |
307 | goto error; |
308 | } | |
309 | buf[n] = '\0'; | |
310 | ||
311 | if (!extra_buf) | |
312 | { | |
313 | extra_buf = malloca (path_max); | |
314 | if (!extra_buf) | |
315 | { | |
316 | freea (buf); | |
49e4877c | 317 | __set_errno (ENOMEM); |
98399780 YQ |
318 | goto error; |
319 | } | |
320 | } | |
321 | ||
322 | len = strlen (end); | |
4c62b19f PA |
323 | /* Check that n + len + 1 doesn't overflow and is <= path_max. */ |
324 | if (n >= SIZE_MAX - len || n + len >= path_max) | |
98399780 YQ |
325 | { |
326 | freea (buf); | |
327 | __set_errno (ENAMETOOLONG); | |
328 | goto error; | |
329 | } | |
330 | ||
331 | /* Careful here, end may be a pointer into extra_buf... */ | |
332 | memmove (&extra_buf[n], end, len + 1); | |
333 | name = end = memcpy (extra_buf, buf, n); | |
334 | ||
335 | if (IS_ABSOLUTE_FILE_NAME (buf)) | |
336 | { | |
337 | size_t pfxlen = FILE_SYSTEM_PREFIX_LEN (buf); | |
338 | ||
339 | if (pfxlen) | |
340 | memcpy (rpath, buf, pfxlen); | |
341 | dest = rpath + pfxlen; | |
342 | *dest++ = '/'; /* It's an absolute symlink */ | |
343 | if (DOUBLE_SLASH_IS_DISTINCT_ROOT) | |
344 | { | |
345 | if (ISSLASH (buf[1]) && !ISSLASH (buf[2]) && !pfxlen) | |
346 | *dest++ = '/'; | |
347 | *dest = '\0'; | |
348 | } | |
349 | /* Install the new prefix to be in effect hereafter. */ | |
350 | prefix_len = pfxlen; | |
351 | } | |
352 | else | |
353 | { | |
354 | /* Back up to previous component, ignore if at root | |
355 | already: */ | |
356 | if (dest > rpath + prefix_len + 1) | |
357 | for (--dest; dest > rpath && !ISSLASH (dest[-1]); --dest) | |
358 | continue; | |
359 | if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 | |
360 | && ISSLASH (*dest) && !ISSLASH (dest[1]) && !prefix_len) | |
361 | dest++; | |
362 | } | |
363 | } | |
364 | else if (!S_ISDIR (st.st_mode) && *end != '\0') | |
365 | { | |
366 | __set_errno (ENOTDIR); | |
367 | goto error; | |
368 | } | |
369 | } | |
370 | } | |
371 | if (dest > rpath + prefix_len + 1 && ISSLASH (dest[-1])) | |
372 | --dest; | |
373 | if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 && !prefix_len | |
374 | && ISSLASH (*dest) && !ISSLASH (dest[1])) | |
375 | dest++; | |
376 | *dest = '\0'; | |
377 | ||
378 | if (extra_buf) | |
379 | freea (extra_buf); | |
380 | ||
381 | return rpath; | |
382 | ||
383 | error: | |
384 | { | |
385 | int saved_errno = errno; | |
386 | if (extra_buf) | |
387 | freea (extra_buf); | |
388 | if (resolved == NULL) | |
389 | free (rpath); | |
49e4877c | 390 | __set_errno (saved_errno); |
98399780 YQ |
391 | } |
392 | return NULL; | |
393 | } | |
394 | versioned_symbol (libc, __realpath, realpath, GLIBC_2_3); | |
395 | #endif /* !FUNC_REALPATH_WORKS || defined _LIBC */ | |
396 | ||
397 | ||
398 | #if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_3) | |
399 | char * | |
400 | attribute_compat_text_section | |
401 | __old_realpath (const char *name, char *resolved) | |
402 | { | |
403 | if (resolved == NULL) | |
404 | { | |
405 | __set_errno (EINVAL); | |
406 | return NULL; | |
407 | } | |
408 | ||
409 | return __realpath (name, resolved); | |
410 | } | |
411 | compat_symbol (libc, __old_realpath, realpath, GLIBC_2_0); | |
412 | #endif | |
413 | ||
414 | ||
415 | char * | |
416 | __canonicalize_file_name (const char *name) | |
417 | { | |
418 | return __realpath (name, NULL); | |
419 | } | |
420 | weak_alias (__canonicalize_file_name, canonicalize_file_name) | |
421 | ||
422 | #else | |
423 | ||
424 | /* This declaration is solely to ensure that after preprocessing | |
425 | this file is never empty. */ | |
426 | typedef int dummy; | |
427 | ||
428 | #endif |